FR2922272A1 - Aerogenerator for producing electrical energy, has rotor placed in upstream of another rotor and axially in convergent section, where rotors and internal surface delimit intake air compression and acceleration chamber - Google Patents

Abstract

An aerogenerator comprises a tubular body (10) with an inlet opening (OA), an exhaust opening (OE), an outer surface (12) which is depressive, an inner surface (13) having a convergent section (T3) connected to it at the inlet opening (OA), a diverging section (T4) connected to the exhaust opening (OE) and the convergent section (T3) by a collar (14), and a first rotor (R1) mounted rotating relative to the tubular body (10) near the neck (14). The rotor (R1) is linked to a first generator machine (G1). It comprises a second rotor (R2) rotatably mounted with respect to the tubular body (10), of a diameter greater than that of the first rotor (R1), placed upstream of the first rotor (R1) in the convergent section (T3) and delimiting, with the inner surface (13) and the first rotor (R1), a chamber for compressing and accelerating (CH) the intake air.

Description

Aerogenerator with two successive rotors Technical field of the invention

The invention relates to an aerogenerator having a tubular body comprising: an air intake opening, an exhaust opening, an external unimpressive surface between the intake opening and the exhaust opening, a inner surface defining an air passage connecting said openings, having a rectilinear flow axis, and having a convergent section connected to the inlet opening, and a diverging section connected to the exhaust opening, said sections being connected by a neck, a first rotor rotatably mounted relative to the tubular body, axially positioned near the neck and connected to a first generator machine.

State of the art

Such wind turbines are known, for example, from JP2005240668 and JP2003028043, for which the inner surface has the general shape of a nozzle. According to the Bernoulli equation, the air admitted is accelerated in the convergent section, this increase in the kinetic energy of the wind being accompanied by a progressive decrease of the pressure. The shape of the diverging section creates an additional depression which has the effect of suctioning the inlet to the outlet (Venturi effect). These known wind turbines have the disadvantage of not having a production

acceptable electrical energy only for a relatively high wind speed, and to have a relatively low overall efficiency given the low value of the ratio between the power captured by the rotor and the power of the wind at the neck.

Furthermore, it has already been imagined in EP1108888 to place two identical rotors parallel to the ends of a cylindrical tubular body and rotating in opposite directions of rotation. Each end of the tubular body is extended by a conical shape, convergent input and divergent output. The action of channeling the air through such a Venturi-type structure (with an increase in the kinetic energy of the air) is accompanied by a pressure decrease in the convergent input portion, then a pressure drop when passing through the input rotor. The latter has the effect of creating a vacuum to accelerate the air in the cylinder before arriving at the output rotor. But low wind efficiency is limited and performance is unsatisfactory for many applications. To supply the depression behind the exhaust opening despite a low wind speed, it is necessary to provide deflectors protruding from the outer face near the exhaust opening. But such deflectors then have the effect of reducing the speed of the air outside, and thus lowering the overall efficiency.

OBJECT OF THE INVENTION The object of the invention is to provide an aerogenerator having increased overall efficiency.

The aerogenerator according to the invention is remarkable in that it comprises a second rotor rotatably mounted relative to the tubular body, of a diameter greater than that of the first rotor, placed upstream of the first rotor.

axially in the converging section and delimiting, with the inner surface and the first rotor, a chamber for compressing and accelerating the intake air.

Unlike the prior art where, upstream of the first rotor placed near the neck, the air was undergoing an increase in kinetic energy combined with a gradual decrease in pressure, the compression chamber and acceleration defined by the two Rotors according to the invention allow the air to undergo an increase in its combined kinetic energy with a progressive increase in pressure. This property allows, at a given wind speed, to increase the production of electrical energy by the first generator.

According to a preferred embodiment, the flow axis is horizontal 15 and the tubular body has a deprimogenic aerodynamic appendage protruding from the outer surface near the exhaust opening. Such an appendage has the effect of increasing the external speed near the exhaust opening and push back the general depression of the wind turbine. The parachute effect (appearance of turbulence at the outlet of the tubular body) occurs for much higher wind speeds.

Other technical features may be used alone or in combination: the second rotor is connected to a second generating machine connected to control means, the second generating machine is a reversible electrodynamic machine, the control means provide a modulation of the rotational speed of the second rotor as a function of the rotational speed of the first rotor, the first and second generating machines are connected to a power management system connected to energy storage means and / or to the electrical network , the energy management system is connected to external power supply means 5, an aerodynamic screen extends axially between the first and second rotors.

BRIEF DESCRIPTION OF THE DRAWINGS Other advantages and features will become more clearly apparent from the following description of particular embodiments of the invention given by way of nonlimiting example and represented in the accompanying drawings, in which: FIG. is an axial sectional view of an exemplary aerogenerator according to the invention, FIG. 2 is a left view of the aerogenerator of FIG. 1, FIG. 3 represents a device for controlling the aerogenerator of the preceding figures. Figure 4 is a view similar to Figure 1 but showing the flow of air.

Description of a preferred embodiment of the invention

With reference to FIGS. 1 to 4, the example of an aerogenerator according to the invention comprises a tubular body 10 mounted to rotate along a vertical axis at the top of a supporting structure 11. The tubular body 10 has a general shape of revolution and therefore has an axis of revolution, which will subsequently correspond to the flow axis X of the air, rectilinear and horizontal. The orientation of the tubular body 10 with respect to the carrying structure 11 is practiced automatically, that is to say freely in

depending on the orientation of the wind, or by an orientation mechanism ensuring that the flow axis X is collinear with the direction of the wind.

At one end (left in Figures 1, 3, 4), the tubular body 10 defines a circular inlet opening OA, for the admission of air in windy conditions. At the opposite end (on the right in FIGS. 1, 3, 4), the tubular body 10 delimits an escape opening OE of circular shape whose diameter is smaller than that of the inlet opening OA. The exhaust opening OE allows the air admitted by the intake opening OA to escape from the tubular body 10.

The tubular body 10 has an outer surface 12 having a wing-shaped aerodynamic profile, with a bulge constituting a diverging section Ti starting from the inlet opening OA and along which the outer diameter increases gradually, and a converging section T2 connecting the section T1 and the exhaust opening OE and along which the outer diameter decreases gradually. Such an aerodynamic profile, combined with the fact that the diameter of the intake opening OA is greater than that of the exhaust opening 0E, has the effect of producing a vacuum at the exhaust opening 0E. The outer surface 12 is therefore deprimogenic between the intake opening OA and the exhaust opening 0E.

The tubular body 10 delimits internally an inner surface 13 having a wing-shaped aerodynamic profile, with a bulge constituting a convergent section T3 connected to the inlet opening OA and along which the inner diameter decreases progressively, and a section diverging T4 connecting the converging section T3 and the exhaust opening OE and along which the inner diameter increases gradually. The two sections T3 and T4 of the inner surface 13 are connected by a neck 14. The inner surface 13 delimits an air passage 15 in the form of a nozzle connecting

the openings OA and 0E, and wherein the air flows along the flow axis X from the inlet opening OA to escape through the exhaust opening 0E.

The aerogenerator comprises a first rotor R1 mounted to rotate relative to the tubular body 10, in an axial position (along the X axis) near the neck 14. The first rotor R1 is connected to a first generator machine G1. The axis of rotation of the rotor R1 coincides with the flow axis X. The first generating machine G1 is an electrodynamic machine generating electrical energy when its rotor is rotated relative to its stator. .

In addition, a second rotor R2 is rotatably mounted relative to the tubular body 10 upstream of the first rotor R1, in an axial position (along the X axis) along the convergent section T3 of the inner surface 13. axis of rotation of the rotor R2 coincides with the flow axis X. The second rotor R2 is connected to a second generator machine G2. More specifically, the second generator machine G2 is a reversible electrodynamic machine. The diameter of the rotor R2 is greater than that of the rotor R1. The rotor R2 delimits, with the inner surface 13 and the first rotor R1, a compression and acceleration chamber CH of the air admitted through the opening OA. In the CH chamber, the air undergoes an increase in kinetic energy along with a gradual increase in pressure as it approaches the first rotor R1. The rotors R1 and R2 each comprise a plurality of blades angularly distributed in a variable pitch. In addition, the rotational direction of the rotors R1 and R2 may be identical or opposite, in order to optimize the overall energy efficiency. 30

In addition to the tubular body 10, the two rotors R1, R2 and the generators G1, G2, the aerogenerator comprises an electronic control device (see FIG. 3) comprising: regulation means 16 of the second generating machine G2, for example integrated in the thickness of the tubular body 10, a sensor 17 measuring a physical parameter associated with the operation of the first rotor R1, a power management system 18, for example integrated in the thickness of the tubular body 10, and connected to storage means 1 o of energy 19, and / or the electrical network 20 and external power supply means 21 in energy.

The two generating machines G1 and G2 are electrically connected to the energy management system 18, respectively via connections 15 identified 22 and 23. The energy management system 18 is electrically connected to the energy storage means 19 by a connection 24, and / or to the electrical network 20 via a connection 25 and to the external power supply means 21 via a connection 26. Finally, the regulation means 16 of the second generator machine G2 are electrically connected to the sensor 17 by a connection 27 and to the second generating machine G2 by a connection 28.

The second generative machine G2 being reversible, it can be driving when it is supplied with electricity, its rotor then being rotated relative to its stator thanks to the energy supplied. The machine G2 can also function as a generator: it generates electrical energy when the rotor R2 imposes on the rotor of the machine G2 a rotational movement relative to its stator.

On the other hand, a not shown reversible coupling system (for example a centrifugal or electromagnetic clutch) is interposed between

the rotor R2 and the second generator machine G2, to ensure a mounting of the rotor R2 free rotation, in case of uncoupling. The connection 28 provides the connection between the coupling system and the regulation means 16.

When the rotor R2 is uncoupled from the generating machine G2, the rotor R2 is in freewheel mode. In the opposite case, the rotor R2 is either in motor mode (corresponding to a motor operation of the generator machine G2) or in generator mode (corresponding to a generator operation of the generator machine G2).

The purpose of the regulation means 16 is to select the mode of operation of the second rotor R2 (motor, generator, or freewheel) which is adapted at each instant. The selection, at any moment, of the operating mode of the second rotor R2 makes it possible to adapt the operation of the second rotor R2 as a function of at least one physical parameter (pressure, speed, temperature, etc.) measured by the sensor 17 and related to the operation of the first rotor R1. The mode of the second rotor R2 is selected by a corresponding action on the second generator machine G2 and on the coupling system, via the connection 28.

For example, by a suitable selection of the operating mode of the rotor R2 at each instant, the regulation means 16 can provide a modulation of the speed of rotation of the second rotor R2 as a function of the rotational speed of the first rotor R1 measured by the sensor 17 when the latter is a tachometer. This type of modulation makes it possible in particular, in steady state, to avoid the rotation of the air in the passage 15. By way of example for effecting such a modulation in speed of the second rotor R2, the regulation means 16 integrate a first control law imposing on the second rotor R2: the motor mode as long as the rotation speed of the first rotor R1 is lower than a first predetermined threshold Q1, the generator mode when the rotational speed of the first rotor R1 is greater than a second threshold predetermined Q2 greater than Q1, the freewheel mode when the rotational speed of the first rotor R1 is between Q1 and Q2. The regulation means 16 can also integrate a second control law, which is a priority over the first control law, and imposes on the second rotor R2 the motor mode as soon as the difference between the speed of rotation of the first rotor R1 and the rotation speed. the second rotor R2 15 is greater than a third predetermined threshold Q3, itself possibly being a function of Q1. The selection of the operating mode of the second rotor R2 is carried out by the regulation means 16 via the connection 28, on the basis of the information received from the sensor 17 via the connection 27.

Whatever the mode of operation imposed on the second rotor R2 by the regulating means 16, the energy management system 18 receives the electrical energy created by the first generator machine G1 via the connection 22. the regulation means 16 impose the motor mode on the second rotor R2, the energy management system 18 transmits the electrical energy required for the second generator machine G2 via the connection 23. When the regulation means 16 impose the generator mode on the second rotor R2, the energy management system 18 receives the electrical energy produced by the

second generating machine G2 via the connection 23. Finally, when the regulating means 16 impose the freewheel mode on the second rotor R2, the energy management system 18 and the second generator machine G2 do not exchange 'electric energy.

In parallel with these energy exchanges with the two generating machines G1, G2, the generated energy management system 18: transmits the energy received from the first generating machine G1 (and possibly from the second generating machine G2 in the event of generator mode of the second rotor R2) to the electrical network 20 via the connection 25 and / or to the energy storage means 19 via the connection 24, and optionally receives, in the event of a motor mode of the second rotor R2, the energy required for driving the second generator machine G2 from the electrical network 20 via the connection 25 and / or from the energy storage means 19 via the connection 24 and / or from the external power supply means 21 via the connection 26.

In order to carry out these operations, the energy management system 18 comprises an interface between the signals exchanged with the generating machines G1, G2 and the signals exchanged with the electricity network 20, the energy storage means 19 and the energy storage means. External power supply 21. Such an interface may for example include transformers, frequency converters and rectifiers.

The strategy carried out by the energy management system 18 with regard to its manner of ordering its exchanges with the other organs of the control device and with the two generators G1, G2 is customizable according to the applications. In particular, transmission to the electrical network 20 may be preferred in certain applications. In

in other cases, the level of energy in the storage means 19 and / or the management of consumption peaks will be preferred.

With reference to FIG. 4, the aerogenerator can be fictitiously decomposed into three successive zones A, B, C offset in the direction of the flow axis X and in the direction of passage of the air. The rear part of the aerogenerator, beyond the exhaust opening 0E, constitutes an additional zone D. The zone A of the aerogenerator corresponds to the part of the aerogenerator located between the plane passing through the opening of the OA inlet 1 o and the plane passing through the end of the diverging section Ti of the outer surface 12. The zone B of the aerogenerator corresponds to the part of the aerogenerator between the zone A and the plane passing through the end convergent section T3 of the inner surface 13. The zone C of the wind turbine is, for its part, constituted by the part of the wind turbine 15 between the zone B and the plane passing through the exhaust opening 0E. As illustrated in FIG. 4, the compression and acceleration chamber CH is included in the zone B of the aerogenerator.

In zone A, irrespective of the mode of operation of the second rotor R2, the flow of the air flow in the passage 15 is accelerated relative to the wind in which the wind turbine is placed. The flow of the airflow sliding on the outer surface 12 is also accelerated with respect to the wind, but of a value less than the acceleration experienced by the air in the passage 15. In the zone B, the outer diameter decreases progressively, which has the effect of creating a depression and therefore an acceleration of the flow of the air flow sliding on the outer surface 12. The flow of the air flow in the passage 15 is it also accelerated along the entire length of zone B because of the convergent nature of the section T3. These inner and outer accelerations occur regardless of the mode of

operation of the second rotor R2. The flow of the air flow in the passage 15 undergoes, parallel to its acceleration, a continuous and progressive increase in pressure along the entire length of zone B. The pressure increase is greater in chamber CH than on the rest of zone B, especially when rotor 2 operates according to the motor mode.

In zone C, the flow of the airflow sliding on the outer surface 12 continues to accelerate. The inner diameter gradually increases to the OE exhaust opening which has the effect of creating an additional depression.

In zone D, the air exiting through the exhaust opening OE is accelerated by the flow of the airflow sliding on the outer surface 12 which has a higher speed. This results in the creation of an additional depression behind the aerogenerator and a rejection of aerodynamic disturbances towards the rear of the wind turbine. The depression generated in zone D helps to maintain the process described previously. This global aerodynamic action makes it possible to accelerate the flow at the inlet of the aerogenerator.

Photovoltaic cells 31 may be provided on all or part of the outer surface 12 to form the external power supply means 21. However, these means may be made by any suitable solution such as a hydraulic source or an auxiliary generator.

The generating machines G1, G2 can be compact and arranged on the flow axis X. In other variants, the generating machines G1, G2 can be in a ring, that is to say that the rotor R1, R2 associated itself constitutes the rotor of the generator machine G1, G2 and the stator is

constituted by a peripheral ring carried vis-a-vis the inner surface 13.

Optionally and as shown, it is possible to provide an aerodynamic screen 30 extending axially between the first and second rotors R1, R2, for example having a cylindrical outer shape, to avoid aerodynamic disturbances near the axis of It is clear that such an aerodynamic screen 30 must maintain the mechanical uncoupling of the rotors R1, R2 between them. In addition, it is possible to consider housing the second generating machine G2 inside the aerodynamic screen.

In the example described above, the flow axis X is horizontal. The tubular body 10 has a predictive aerodynamic appendage 29 projecting from the outer surface 12 near the exhaust opening 0E. This appendix 29 makes it possible to accentuate the acceleration experienced by the flow of the air flow sliding the convergent section T2 of the outer surface 12, and considerably reduces the noise produced by the flow of air on the outer surface 12 The parachute effect (appearance of turbulence at the outlet of the tubular body 10) occurs for much higher wind speeds than in the absence of appendix 29.

The aerodynamic appendix 29 has the shape of a ring held at a distance around the tubular body 10 and having an inner face facing the outer face 12, and an opposite outer face. In a sectional plane passing through the flow axis X, the inner face of the crown has a convex aerodynamic profile with a bulge directed towards the outer surface 12, while the outer face of the crown has a concave aerodynamic profile with a hollow directed towards the outer surface 12.

Although it has been described in a variant where the flow axis X is horizontal, the aerogenerator according to the invention can be adapted to have a vertical axis of flow. In such a variant, the shape of the outer surface 12 may be modified so as to have a concave or convex profile of spherical shape. On the other hand, whatever the variant chosen (horizontal or vertical axis of flow), the shape of the inner and outer surfaces is not limited to that of FIGS. 1 to 4 and can be modified, since the surface The outer surface remains a pressure differential between the inlet opening OA and the exhaust opening 0E, and the inner surface comprises a convergent section and a diverging section connected by a collar.

It is possible to provide a mechanical brake associated with each rotor R1, R2. On the other hand, the control device described above can include functions for carrying out economic and energy balances as well as maintenance forecasts, and remains optional because the wind turbine may have no element for regulating and managing energy. .

Finally, several wind turbines according to the invention can be combined in horizontal and / or vertical cascades, on a circular axis and / or on different axes and planes. To identify each of the wind turbines, a radiofrequency label can be associated with each turbine.

Claims (9)

claims An aerogenerator having a tubular body (10) comprising: an air intake opening (OA), an exhaust opening (OE), an outer surface (12) that is pressure-relieving between the inlet opening (OA) and the exhaust opening (0E), an inner surface (13) delimiting an air passage (15) connecting said openings (OA, OE), having a rectilinear flow axis (X), and having a section convergent (T3) connected to the inlet opening (OA), and a diverging section (T4) connected to the exhaust opening (OE), said sections (T3, T4) being connected by a collar (14) , a first rotor (R1) rotatably mounted with respect to the tubular body (10), axially positioned near the neck (14) and connected to a first generating machine (G1), characterized in that it comprises a second rotor (R2) rotatably mounted with respect to the tubular body (10), of a diameter greater than that of the first rotor (R1), placed upstream of the first rotor ( R1) axially in the convergent section (T3) and delimiting, with the inner surface (13) and the first rotor (R1), a compression and acceleration chamber (CH) of the intake air. 2. The aerogenerator according to claim 1, characterized in that the flow axis (X) is horizontal and the tubular body (10) has a projection-like aerodynamic appendage (29) projecting from the outer surface (12) in the vicinity. the exhaust opening (0E). 3. Aerogenerator according to one of claims 1 and 2, characterized in that the second rotor (R2) is connected to a second generating machine (G2) connected to control means (16). 4. Aerogenerator according to claim 3, characterized in that the second generator machine (G2) is a reversible electrodynamic machine. 5. Aerogenerator according to one of claims 3 and 4, characterized in that the regulating means (16) adapt the operation of the second rotor (R2) as a function of at least one physical parameter related to the operation of the first rotor (R1 ). 10 6. Aerogenerator according to claim 5, characterized in that the regulating means (16) provide a modulation of the rotational speed of the second rotor (R2) as a function of the speed of rotation of the first rotor (R1). Wind turbine according to one of Claims 3 to 6, characterized in that the first and second generating machines (G1, G2) are connected to a power management system (18) connected to storage means energy (19) and / or the electrical network (20). 8. The aerator according to claim 7, characterized in that the energy management system (18) is connected to external power supply means (21) in energy. 25 9. Aerogenerator according to one of claims 1 to 8, characterized in that an aerodynamic screen (30) extends axially between the first and second rotors (R1, R2). 15 20